This study investigates and organizes high-performance techniques achieved by multi-phase permanent magnet synchronous motor (PMSM) systems. Authors propose several techniques to improve torque density and/or efficiency based on multi-phase PMSM systems such as six-phase open winding motor systems and multi three-phase motor systems. In this paper, motor winding configurations and difference of these motor systems are discussed from the viewpoint of their control freedoms. The applicability of high-performance technology to each motor system is described. As a result of this study, it is revealed that there are five freedoms achieved by multi-phase PMSM systems. This paper categorizes each proposed system from the viewpoint of achieving freedom and applicable techniques such as efficiency improvement.